The field of the present invention relates to a cargo lock device that holds cargo pallets in place within vehicles such as aircraft. The aircraft includes seat or cargo tracks located in the cargo floor. The seat tracks are located in the cargo floor and run lengthwise through the aircraft. The seat tracks are supported at regular intervals typically by transverse floor beams. Typically, the cargo lock device includes hooks referred to as pawls and a number of support rollers. The device is connected to a seat track by means of tensile studs and shear ties. The studs restrain the lock against vertical motion and the shear ties restrain the lock against horizontal motion.
The present inventor has recognized that these cargo locks are structurally inefficient for the aircraft floor because of their geometry and the locations of their studs, shear ties and rollers relative to the pawls. With the lock in an unfavorable position in the seat track relative to the transverse floor beams, most of the load applied by the cargo pallet will transfer through just one floor beam. This situation occurs when the stud that is closest to the pawls is located directly over top of a floor beam. For example, U.S. Pat. No. 5,433,564 discloses a device which employs a resiliently deformable section in its floor hooks, but does not disclose relative distribution of tensile forces relative to floor support points.
The existing lock designs may minimize cost and weight of the locks themselves, but these cost and weight savings are disadvantageously offset by the additional structure required in the transverse floor beams and the seat tracks.
The present invention is directed to an improved cargo locking device for locking of freight in a vehicle such as the stowage of containers, or pallets in aircraft. The improved cargo locking device avoids the aforementioned disadvantages by arranging track connectors, e.g. the tensile studs, in such a manner that tensile load is distributed between the floor beams.
In its preferred embodiment, the cargo lock has a lock length about equal to or exceeding the transverse beam pitch. The tensile studs will be placed in groups at both ends of the lock. The pawls will be placed in the middle of the lock. This arrangement will split the pawl loads (from the cargo pallet) between the forward and the aft stud. The separation of the studs is such that the combined loading from the two groups of studs into a single transverse floor beam never exceeds about 50% of the pawl load. The invention will now be described further as illustrated on the attached drawings of examples of its preferred embodiments.